Top PDF Dust deposition in Antarctica in glacial and interglacial climate conditions: a modelling study

Dust deposition in Antarctica in glacial and interglacial climate conditions: a modelling study

Dust deposition in Antarctica in glacial and interglacial climate conditions: a modelling study

Delmonte, B., Baroni, C., Andersson, P. S., Schoberg, H., Hansson, M., Aciego, S., Petit, J.-R., Albani, S., Mazzola, C., Maggi, V., and Frezzotti, M.: Aeolian dust in the Talos Dome ice core (East Antarctica, Pacific/Ross Sea sector): Victoria Land versus remote sources over the last two climate cycles, J. Quaternary Sci., 25, 1327–1337, doi:10.1002/jqs.1418, 2010b. 3727 DeMott, P. J.: African dust aerosols as atmospheric ice nuclei, Geophys. Res. Lett., 30, 1732,

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Modelling of mineral dust for interglacial and glacial climate conditions with a focus on Antarctica

Modelling of mineral dust for interglacial and glacial climate conditions with a focus on Antarctica

Our results suggest the increase in dust deposition in Antarctica for all considered time slices relative to the pre- industrial period. In the mid-Holocene and Eemian dust de- position is increased by a factor of 2.8 and 2.7, respectively. Approximately two-thirds of the increase in both periods is attributed to enhanced Southern Hemisphere dust emissions. Slightly strengthened transport efficiency due to southward deflection of the transport pathway causes the remaining one- third of the increase in dust deposition. Compared to pre- industrial conditions, more intensive poleward transport at 115 000 yr BP together with almost similar Southern Hemi- sphere emissions results in only slightly enhanced dust depo- sition in Antarctica. The highest dust deposition in Antarctica is simulated for the LGM, showing a 10.2-fold increase com- pared to CTRL. This results from a combination of 2.6 times higher Southern Hemisphere dust emissions, 2 times stronger transport and 30 % weaker precipitation over the Southern Ocean. Our finding supports the suggestions by other stud- ies (e.g. Krinner et al., 2010; Krinner and Genthon, 2003) of more intensive atmospheric poleward transport during the glacial period.
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Sea ice led to poleward-shifted winds at the Last Glacial Maximum: the influence of state dependency on CMIP5 and PMIP3 models

Sea ice led to poleward-shifted winds at the Last Glacial Maximum: the influence of state dependency on CMIP5 and PMIP3 models

A wide range of palaeodata has been interpreted as evi- dence for glacial to interglacial jet shifts. These data include proxies, or direct measurements of, terrestrial moisture, dust deposition, sea surface temperatures, and ocean productiv- ity. Kohfeld et al. (2013) find that purely based on these palaeodata, one can hypothesise a variety of wind change scenarios including: no change, a southward shift, and a northward shift. It remains an extraordinarily difficult task to constrain glacial to interglacial jet shifts and intensifica- tions based on data alone (Hodgson and Sime, 2010). Whilst Sime et al. (2013) find that the moisture change palaeodata can be accurately modelled under a no jet shift scenario, Ko- hfeld et al. (2013) suggest that an equatorward jet shift, or intensification, could also be consistent with the majority of the palaeodata. Efforts to help solve this jet change problem using GCMs have benefitted from the fifth Coupled Model Intercomparison Project (CMIP5), specifically the third Pa- leoclimate Modelling Intercomparison Project (PMIP3), and its predecessor PMIP2 (Braconnot et al., 2007, 2012; Taylor et al., 2011). PMIP2 and PMIP3 have provided ensembles of LGM and pre-industrial (PI) climate simulations, where each model is run under the same boundary conditions, permit- ting inter-model comparisons and insight into crucial wind change mechanisms (e.g. Roche et al., 2012; Rojas, 2013; Chavaillaz et al., 2013; Sime et al., 2013; Liu et al., 2015).
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Investigating The Use Of Mobile Computing In Zimbabwe Polytechnics Case Of A Polytechnic In Zimbabwe

Investigating The Use Of Mobile Computing In Zimbabwe Polytechnics Case Of A Polytechnic In Zimbabwe

1. INTRODUCTION In the period prior to 2003 Polytechnics in Zimbabwe had a mix of Information Communication Technologies (ICTs), varying from one institution to the other. There was no uniformity as to what ICTs individual institutions invested in, so while some institutions had several computer laboratories of clone desktops, some did not have even a single lab. While some had connected to the internet through the dialup system which came through telephone lines, some had no idea what internet was.A breakthrough came in 2003 when a non- governmental organization called VVOB, a Belgian abbreviation which translates in English to Flemish for Technical Assistance, came in with a project called the College Information Technology Enhancement Programme (CITEP), which helped to finance, train personnel and equip polytechnics with standard computer and network infrastructure (VVOB project document, 2003). They conducted training workshops for personnel, procured standard desktops, and installed fibre internet connectivity and setup Ethernet networks in these institutions. This project became the basis for mobile computing in Polytechnics. When the project ended in 2008, the institutions were now coordinated and some managed to go a step further by installing wireless access points within institutions using the fibre backbone. This allowed staff and students who had WIFI enabled devices to be able to access internet and research
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What controls deuterium excess in global precipitation?

What controls deuterium excess in global precipitation?

spatial grid. RH above the ocean surface has then been cal- culated as described above. In addition, sea ice cover, sur- face latent heat flux (which is proportional to surface evap- oration) and land surface temperature have also been taken from the reanalysis data. The latent heat flux (LHF) is a fore- cast field, and forecast steps from 6 to 12 and 12 to 18 h are used, neglecting the first 6 h because of possible model spin- up effects. Near-surface humidity is reasonably well repre- sented in the ERA-Interim data (Simmons et al., 2010; Pfahl and Niedermann, 2011), and using such a reanalysis data set is decisive because of the best possible spatial and tempo- ral coverage it offers. The linear regression model described above has been applied to calculate d of water evaporating from the ocean for each six-hourly time step and each grid point, taking the reanalysis RH as input. The uncertainty of the linear regression is used as an uncertainty estimate for predicted d. Note that this estimate does not account for the uncertainties of the individual d and RH measurements and should thus be considered as lower bound of the model uncertainty. Taking errors of individual data points into ac- count is hardly possible, since these depend on various fac- tors such as the related moisture source footprint. Climato- logical means of d have been obtained at every grid point and for each month and season by averaging the correspond- ing six-hourly values, weighted with the six-hourly surface latent heat flux. Finally, hemispheric means have been cal- culated by averaging d over all grid boxes in the respec- tive hemisphere, weighted with the grid box surface area and mean latent heat flux. The weighting with latent heat flux (or, equivalently, surface evaporation) is necessary to com- pare with the precipitation-weighted GNIP data (see below) and to close the d budget of the atmospheric water cycle.
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An Analysis Of The Difference In Gender Level Of Cassava Production And Access To Land In Abia State Nigeria

An Analysis Of The Difference In Gender Level Of Cassava Production And Access To Land In Abia State Nigeria

technique was employed in sample selection. In the first stage, the three agricultural zones in the state were purposively selected. Aba, Umuahia and Ohafia. In the second stage three local governments actively involved in agricultural production was purposively selected from each of the agricultural zone making it a total of nine blocks. While In the third stage two communities was randomly selected from each of the local government. Twelve respondents was randomly selected from two sampling group. six each for male and female giving twelve respondents from each cell. A total of 218 respondents was selected for the study. The research instrument used for this study was structured questionnaire and scheduled interview. The result of the objective of the study was analyzed using descriptive statistics such as frequency, percentage, and mean inferential which involves the use of Z-test analysis. The formula used to compute the mean used in this study is specified below. The mean was computed by multiplying the frequency (f) of the responses under each response category by assigned value and dividing the (∑) of the product by the (N) no of respondents to the particular indicator as shown:
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An ice sheet model of reduced complexity for paleoclimate studies

An ice sheet model of reduced complexity for paleoclimate studies

Balmaseda, M. A., Balsamo, G., Bauer, P., Bechtold, P., Beljaars, A. C. M., van de Berg, L., Bidlot, J., Bormann, N., Delsol, C., Dragani, R., Fuentes, M., Geer, A. J., Haimberger, L., Healy, S. B., Hersbach, H., Hólm, E. V., Isaksen, L., Kållberg, P., Köhler, M., Matricardi, M., McNally, A. P., Monge-Sanz, B. M., Morcrette, J.-J., Park, B.-K., Peubey, C., de Rosnay, P., Tavolato, C., Thépaut, J.-N., and Vitart, F.: The ERA-Interim reanalysis: configuration and

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Mineral dust variability in central West Antarctica associated with ozone depletion

Mineral dust variability in central West Antarctica associated with ozone depletion

all sea salt compounds in the sample. Insoluble elements/compounds detected were Al, Cr, Cu, Fe, Ni, S, Si, Ti, W, V, AlSi, AlTi, AlSi-Cl, AlSi-Fe, AlSi-Mg, AlSi-S, AlSi-Ti, AlSi/FeCl, Fe-Cr, FeSi, FeSi-S, Fe-Cr-W, KCl, SiCl, SiS, SiS Cu, SZn, TiSi, V-Cr, V-Fe, V Cr, Fe W and V Cr Si. Herein, time series for mineral dust were denoted by F AlSi and F Fe (Fig. 1a). In this case insoluble dust microparticles presented similar trends with re-

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Biotic interactions overrule plant responses to climate, depending on the species' biogeography.

Biotic interactions overrule plant responses to climate, depending on the species' biogeography.

We secondly hypothesised that the changing climate conditions in our study have a different impact on the transplants with respect to their range type. The expectation that species of the oceanic plant range type perform better at the oceanic end of the climate gradient and those of the continental plant range type at the continental end of the climate gradient was not confirmed. Instead, we even found opposing patterns with increased incidence of flowering, plant height and aboveground biomass for continen- tal plants under moister conditions and for oceanic plants under drier conditions. These results support the outcome of previous experiments in the field and the greenhouse, where analyses with the same species set revealed similar responses to manipulated climate change [28] or altered soil moisture conditions [21,22]. Nevertheless, at least for the continental species, we expected a Figure 3. Summary of interactive effects of competition and herbivory on species with different plant range types for survival (A,B), plant height (C,D) and number of flowering units (E,F). Effects for the oceanic species are illustrated on the left side (A,C,E), for continental on the right side (B,D,F). The values in the bottom left corner are LSmeans estimates calculated from the GLMM for the treatment without biotic interactions. The values on the arrows are differences in the LSmeans estimates of this treatment-combination indicating the direction and strength of the relation. Units are percentage (A,B), cm (C,D) and numbers (E,F). Bold arrows indicate significant effects according to the Tukey post hoc-test. ***p,0.001, **p,0.01, *p,0.05.
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Global distribution and radiative forcing of soil dust aerosols in the Last Glacial Maximum simulated by the aerosol climate model

Global distribution and radiative forcing of soil dust aerosols in the Last Glacial Maximum simulated by the aerosol climate model

considering variation of the soil moisture, but they were still lower than values reported from ice cores. They indicated that inclusion of more realistic boundary conditions for the dust emission (e.g., vegetation) could also improve the LGM dust cycle. Mahowald et al. (1999) showed that the simulated dust deposition flux in the LGM were roughly in agreement with observed data from marine sediments and ice cores by including

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Overeducation, undereducation and labor earnings in Brazil: a panel data analysis

Overeducation, undereducation and labor earnings in Brazil: a panel data analysis

10 However, taking into account individuals’ fixed effects, the estimated coefficients fall substantially, as shown in column (2). The estimated impact for each year of surplus schooling on labor earnings drops from 10.7% in column (1) to 0.9% in column (2), whereas the estimated penalty for each additional year of deficit schooling drops from 11.5% to 1.1%. Differences regarding the coefficients in columns (1) and (2) of Table 3 are similar to those found in studies for other countries, underlining the argument that unobserved time-invariant factors play an important role. In spite of the reduction in estimated effects, both undereducation and overeducation coefficients remain statistically significant at the 1% level in the fixed effects model. Table 3 also reports F-tests of the joint equality b 1 =b 2 = -b 3 , which indicates that years of required
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Corrigendum to "Impact of CO<sub>2</sub> and climate on the Last Glacial Maximum vegetation: results from the ORCHIDEE/IPSL models" published in Clim. Past, 7, 557&ndash;577, 2011

Corrigendum to "Impact of CO<sub>2</sub> and climate on the Last Glacial Maximum vegetation: results from the ORCHIDEE/IPSL models" published in Clim. Past, 7, 557&ndash;577, 2011

Last Glacial Maximum vegetation: results from the OR- CHIDEE/IPSL models” by M.-N. Woillez et al., Fig. 14 has been accidentally replaced by the same figure as Fig. 13 in the final published manuscript. The Sect. “4.2.4 Impact of LGM CO 2 for a modern background climate” on p. 571, sec-

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Implementation and testing of a desert dust module in a regional climate model

Implementation and testing of a desert dust module in a regional climate model

The SHADE experiment provided data for the characteriza- tion of the vertical structure of the dust outbreak by use of lidar measurements along plane trajectories as well as lo- cal drop sound measurements (L´eon et al., 2003; Tanr´e et al., 2003). Here, we compare simulated vertical cross sec- tions of extinction to lidar back scattering coefficients taken from L´eon et al. (2003). The lidar measurement is linked to the aerosol extinction as described by L´eon et al. (2003). As a first order approximation, we assume that both the li- dar and modeled extinction profiles are proportional to the actual amount of dust in a given atmospheric layer. Rather than assessing the absolute magnitude, we instead focus on the relative magnitude and position of the simulated vs. ob- served dust layers. The simulated values at 40 km resolution have been interpolated from the original sigma level grid to a regular height grid for comparison. Note that the model was run at its standard configuration (targeted for climate appli- cations) which includes 18 vertical sigma levels with a mid- tropospheric resolution of about 90 hPa. This is admittedly a relatively coarse vertical resolution.
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SOWING PERFORMANCE BY A METERING MECHANISM OF CONTINUOUS FLOW IN DIFFERENT SLOPE CONDITIONS

SOWING PERFORMANCE BY A METERING MECHANISM OF CONTINUOUS FLOW IN DIFFERENT SLOPE CONDITIONS

The seeds had average water content of 12.92% and they are in conformity with the 29/2011 normative ruling of the Ministry of Agriculture, Livestock, and Supply, which determines maximum value of water content of 13% for sorghum seeds. According to ANDRADE et al. (1999), the seed water content has an important influence on the mechanical damage; dry seeds are more susceptible to crack and break than the wet seeds and can be understood as an effect of lower plasticity to the speed impact with the rotor of metering mechanism.

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Electronic Government In Democratic Public Service In One Door Integrated Permit Handling Services Agency In The City Of Samarinda

Electronic Government In Democratic Public Service In One Door Integrated Permit Handling Services Agency In The City Of Samarinda

As state institutions, it should be possible to present and make use of electronic government in the function of serving the community. The emphasis in information technology to avoid the digital gap in at least. The provision of better government services to residents, increase interaction with the business world and industry, through access to information for community empowerment, a more efficient government or management. The results of that is expected of a reduction in corruption, the increase in transparency, the increase in comfort, and rising income or reducing expenses. Based on the results of research. Electronic government in the context of the ability to look the ability to run the function of government electronic media and build partnerships with private not optimal it is marked with the need for the allocation of fund optimally and support to work jointly with private companies to more so handling equipment and support for the success of electronic government could be achieved. As an effort to harmonize the acceleration of the completion of work, the licensing of the city of Samarinda must be able to implement the interests of citizens as well as problems faced by. No service to stop because of the support of funding led to the ability to reform it weakened to find appropriate formulations to stiffness in public service is not of stagnation. According to results of the review Khidasseli in Sutedi (2010) that norms behavior officers public service providers (a code of conduct for public officials), who set about norms in an administrative authority: 1) The obligation to work in accordance with the rules of law and standards of conduct of relevance to its function, 2) The obligation to put themselves in a neutral of or free from the
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Application of sediment core modelling to understanding climates of the past: An example from glacial-interglacial changes in Southern Ocean silica cycling

Application of sediment core modelling to understanding climates of the past: An example from glacial-interglacial changes in Southern Ocean silica cycling

minimum (summer-time) limit may have been little changed (Crosta et al., 1998) con- trary to CLIMAP (CLIMAP, 1976). Driving the model with a seasonal sea-ice forcing making this alternative (summer-time) assumption results in little variability in opal con- tent (<5 wt%) occurring either side of the APF. That the CLIMAP reconstruction enables the better fit to the opal data does not support any drastic revision of CLIMAP being

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Charter Schools, Equity and Efficiency in Public Education

Charter Schools, Equity and Efficiency in Public Education

Studies of the first type (longitudinal) tend to have a broader scope, covering various educational districts or states, whereas the second type of studies (lotteries) focus on minority students and on large urban districts. For example, Clark et al. (2011) present the results of a randomized national study that includes 36 charter schools in 15 U.S. States finding that, on average, the performance of charter schools is no different from that of traditional public schools. However, the results vary significantly among schools and students, with positive effects for disadvantaged students and schools and negative effects for the most socially advantaged students and schools. Similarly, Angrist et al. (2013) find that, in the state of Massachusetts, the impact of charter schools is positive in urban areas (where the population tends to be socially disadvantaged) and negative (or not significant) in non-urban areas.
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Nigeria SMEs P articipation in  E lectronic  E conomy:  Problems and the  W ay  F orward

Nigeria SMEs P articipation in E lectronic E conomy: Problems and the W ay F orward

Firms need to attract attention to their products and services. This could prove to be quite a task for the typical Nigeria firm, with a practically unknown brand name and weak advertising dollars. Goldstein and O’Connor (2001) state that “even the best e-marketing strategy does not substitute for traditional media. Indeed, such advertising is normally viewed as an unavoidable sunk cost to establish brand name recognition.” Small firms by themselves will be unable to afford the advertising sunk cost that is necessary for effective market penetration. By engaging in a cooperative effort in marketing, using a Web portal and sharing advertising cost, firms may better penetrate the on-line market. Nigeria government needs to encourage and recognize innovative applications of ICTs and help in instituting mechanisms to spread best practices. Government should create a national demonstration and help desks to assist SMEs in ICTs choice, implementation and maintenance. If possible, provide motivation to encourage SMEs’ use of ICTs through various mechanisms, facilitate, support and encourage e-commerce applications through establishing appropriate frameworks, removing hurdles and leading by example. There is need for education and training. Education institutions in Nigeria should Institute compulsory courses in information and communications technology as early as possible into the curriculum. They should also encourage local hardware shops to collect- refurbish and roll-out computers that are gathering dust in most offices to high schools and elementary schools, at least where there is electricity, so that students will get exposure at an early age.Education administrators must ensure that tertiary education curriculum reflects changes in the global environment, expand tertiary level information and communications technology education, establish specialized institutions (like the Egyptian Information technology and South African software development institute) to prepare young cadres for the information economy in collaboration with the local private sector and other international institutions.In addition, they should also encourage, recognize, accredit and certify private institutions involved in high level ICTs training, set requirements and (social) obligations for organizations to provide ICTs skills to their staff and provide incentive and motivation.
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Wet and dry deposition of mineral dust particles in Japan: factors related to temporal variation and spatial distribution

Wet and dry deposition of mineral dust particles in Japan: factors related to temporal variation and spatial distribution

As described in Sect. 3.1, wet deposition fluxes at Toyama and Tottori were much higher than that in Nagoya where precipitation frequency was low. Because dust particles are transported by westerly wind to the east, and because west- ern sites of the Japanese Islands are influenced by frequent drizzle during dusty seasons, dust particles are depleted dur- ing air mass passage over the Japanese archipelago as if dust particles are washed out by precipitation along the western side of the Japanese islands. The distance between Toyama and Nagoya is about 170 km. Therefore, finer horizontal res- olution is necessary to simulate the small scale difference of wet deposition properly. Indeed, large-scale transport mod- els have difficulty reproducing the transport of large dust particles (Zendar et al., 2004). Reportedly, a counteracting process to gravitational settling exists for particles of 10– 50 µm at higher wind speeds, but the mechanism responsi- ble for this phenomenon was not fully understood (Aluko and Noll, 2006). They claim that this can promote their abil- ity for long range transport of giant dust. Another possible process changing vertical dust distribution is the convective transport of dust particles (Jung et al., 2005). Dust size larger than 10 µm is important for the mass of wet and dry deposi- tion. Therefore, further analysis and simulation of giant dust particle behavior in the atmosphere is necessary to ascertain actual dust effects on biogeochemical cycles as well as their climatic significance.
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Simulating the vegetation response in western Europe to abrupt climate changes under glacial background conditions

Simulating the vegetation response in western Europe to abrupt climate changes under glacial background conditions

The vegetation simulated at the end of ONtoOFF grad is presented in Fig. 3b (absolute vegetation fractions) and Fig. 3c (anomalies). The main differences between ON- toOFF grad and ON ctrl are an increase of forests over East Brazil, a decrease over central America and equatorial Africa, a reduction of forests over Western Europe, replaced by grasses, and a decrease of grasses over the Beringia re- gion. The increase of forest over South America at the ex- pense of the bare soil fraction is due to the strong increase of precipitation over this area in response to the displacement of the ITCZ (Fig. 2b). The opposite trend is simulated at the end of OFFtoON grad and OFFtoON fast compared to ON ctrl: the decrease in precipitation leads to a decrease in trees frac- tions (Fig. 4a, b). This result is in qualitative agreement with pollen data for South America (Hessler et al., 2010). The records with sufficiently high resolution to investigate the re- sponse of vegetation to millennial-scale variability in this re- gion are rather sparse, however a few sites from the northern and southern present-day limit of the ITCZ support the hy- pothesis of a southward migration of the ITCZ during HE events: in the Cariaco Basin, interstadials are characterized by an expansion of forests and stadials by the dominance of savannah, whereas records from northeastern Brazil show
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